A head-mounted display system mounts to the head of a user such that the user may view an image produced by it. Generally, the display functions as a conveniently located interface with a computer, which may be included in the head-mounted display system. For example, a head-mounted display system may provide an aircraft pilot with maps and other information related to the real scene that the pilot is viewing. Some head-mounted display systems, described as “see-through,” allow the user to view a displayed image at the same time as viewing a real scene in the user's line of sight. See-through head-mounted display systems overlay a display image on a real scene viewed by the user. Recent advances in micro-optics manufacturing have resulted in the development of see-through head-mounted display systems targeted for the consumer market, where the display system may provide functionality similar to that of a smartphone.